ZBLAN (Zirconium, Barium, Lanthanum, Aluminum, Sodium fluoride) is a type of heavy metal fluoride glass that, when drawn into optical fiber in microgravity, can theoretically achieve signal attenuation 10-100 times lower than conventional silica fiber. On Earth, gravity-induced crystallization creates microdefects that degrade performance, but in microgravity these defects are suppressed.
ZBLAN fiber has been produced in small quantities on the ISS and on parabolic flights, with results confirming the theoretical microgravity advantage. Companies including Flawless Photonics are working to scale production on commercial space stations. If space-manufactured ZBLAN achieves its theoretical performance at scale, it could command prices of $100,000+ per kilometer, potentially making it one of the first commercially viable in-space manufactured products with sufficient value density to justify the cost of orbital production and re-entry.